digitalmars.D.learn - Cryptic Error message with scope(failure) and AA
- Anthony Goins (24/24) Jun 29 2013 Is this known?
- monarch_dodra (31/55) Jun 29 2013 Seems like there are several levels of "wrong" actually: What do
- Jonathan M Davis (4/7) Jun 29 2013 I thought that there was a bug report on that (probably suggesting that ...
- bearophile (5/9) Jun 29 2013 If you can't find it, it's better to file it because it's better
- =?UTF-8?B?QWxpIMOHZWhyZWxp?= (7/9) Jun 29 2013 Hmmm... 'continue' and others are disallowed only for scope(exit) and
- Anthony Goins (10/12) Jun 29 2013 I was reading an array of files (Document[string]).
Is this known? I've heard there are many problems with associative arrays. dmd 2.063 --- module scopefailtest; int[char] AAarray; void main(string[] args) { AAarray = ['a':1, 'b':2, 'c':3]; foreach(aa; AAarray) { scope(failure)continue; aa = 32; } } --- dmd output Error: cannot implicitly convert expression (0) of type int to void Works without scope(failure) Works with non Associative Array No helpful description. No file or line number. Very hard to find.
Jun 29 2013
On Saturday, 29 June 2013 at 20:45:12 UTC, Anthony Goins wrote:Is this known? I've heard there are many problems with associative arrays. dmd 2.063 --- module scopefailtest; int[char] AAarray; void main(string[] args) { AAarray = ['a':1, 'b':2, 'c':3]; foreach(aa; AAarray) { scope(failure)continue; aa = 32; } } --- dmd output Error: cannot implicitly convert expression (0) of type int to void Works without scope(failure) Works with non Associative Array No helpful description. No file or line number. Very hard to find.Seems like there are several levels of "wrong" actually: What do you expect "scope(failure)continue" to do exactly? It compiles, but it doesn't make much sense? When I run this code: -------- void main(string[] args) { foreach(aa; 0 .. 3) { scope(failure){writeln("error");continue;} writeln(aa); throw new Exception(""); } } -------- I get: -------- 0 error 1 error 2 error -------- Which is wrong, since a scope(failure) is not supposed to "catch" the exception. In this case, the "continue" short-circuits the compiler generated "rethrow". DMD is on to something, because if you replace failure with "exit" or "success", then it complains with: "Error: continue is not inside a loop".
Jun 29 2013
On Saturday, June 29, 2013 23:26:33 monarch_dodra wrote:Which is wrong, since a scope(failure) is not supposed to "catch" the exception. In this case, the "continue" short-circuits the compiler generated "rethrow".I thought that there was a bug report on that (probably suggesting that the compiler make such a continue illegal), but I can't find it right now. - Jonathan M Davis
Jun 29 2013
Jonathan M Davis:I thought that there was a bug report on that (probably suggesting that the compiler make such a continue illegal), but I can't find it right now.If you can't find it, it's better to file it because it's better to have a bug two times in Bugzilla than no times. Bye, bearophile
Jun 29 2013
On 06/29/2013 02:26 PM, monarch_dodra wrote:DMD is on to something, because if you replace failure with "exit" or "success", then it complains with: "Error: continue is not inside a loop".Hmmm... 'continue' and others are disallowed only for scope(exit) and scope(success): http://dlang.org/statement.html#ScopeGuardStatement "A scope(exit) or scope(success) statement may not exit with a throw, goto, break, continue, or return; nor may it be entered with a goto." Ali
Jun 29 2013
Seems like there are several levels of "wrong" actually: What do you expect "scope(failure)continue" to do exactly?I was reading an array of files (Document[string]). Stuck the scope(failure)continue in late at night apparently to skip reading files that no longer exist. Forgot about it. Still don't remember doing it. Next day tried to build my project (30+ files). I had no clue what was going on given the error message. The problem for me was not the error itself but the message. Thanks for the reply. Didn't realize there was a problem with 'continue' from a scopeguard.
Jun 29 2013